Intelligent network for chemical dispensing system

ABSTRACT

System and method for dispensing product to a washing machine. A chemical dispensing system includes a system controller, machine interface, and pump controller that communicate through serial data buses. The system controller provides a user interface, retrieves washing machine status information from the machine interface, and issues product dispensing commands to the pump controller. The pump controller monitors pump status and dispenses product in response to commands from the system controller. The pump controller: (1) determines pump activation periods based on calibration data stored in a pump controller memory; (2) tracks pump usage and adjusts the activation period to compensate for pump wear as the pump ages; (3) disables the pump if conditions exists that preclude operating the pump; (4) monitors product levels, and (5) reports pump status to the system controller. Integral channels are included in the pump housing to provide stress relief to a squeeze tube.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, co-pendingapplication Ser. No. 15/232,386, filed Aug. 9, 2016, which is adivisional of application Ser. No. 13/273,581 filed Oct. 14, 2011 (whichissued as U.S. Pat. No. 9,447,536 on Sep. 20, 2016), the disclosures ofwhich are expressly incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The invention relates generally to chemical dispensing systems forlaundry, ware-wash, and healthcare, and more particularly to systems andmethods for automatic control of product dispensing in a chemicaldispensing system.

BACKGROUND OF THE INVENTION

The dispensing of liquid chemical products from one or more chemicalreceptacles is a common requirement of many industries, such as thelaundry, textile, ware wash, healthcare instruments, and food processingindustries. For example, in an industrial laundry facility, one ofseveral operating washing machines will require, from time to time,aqueous solutions containing quantities of alkaloid, detergent, bleach,starch, softener and/or sour. Increasingly, such industries have turnedto automated methods and systems for dispensing chemical products. Suchautomated methods and systems provide increased control of product useand reduce human contact with potentially hazardous chemicals.

Contemporary automatic chemical dispensing systems used in thecommercial washing industry typically rely on pumps to deliver liquidchemical products from bulk storage containers. Generally, these pumpsdeliver raw product to a washing machine via a flush manifold, where theproduct is mixed with a diluent, such as water, that delivers thechemical product to the machine. A typical chemical dispensing systemused to supply a washing machine will include a controller that iscoupled to one or more peristaltic pumps in a pump-stand by a pluralityof dedicated signal lines. The controller will also typically be coupledto a washing machine interface by another plurality of dedicated signallines, so that the controller is provided with signals indicating theoperational state of the machine. In operation, the machine interfacetransforms high voltage trigger signals generated by the washing machineinto lower voltage signals suitable for the controller, and transmitsthese low voltage trigger signals to the controller over the set ofdedicated signal lines, which are typically in the form of amulti-conductor cable. In response to these individual trigger signals,the controller will individually activate one or more of the pump-standsover another set of dedicated lines so that the pumps dispense a desiredamount of a chemical product into the flush line. The chemicals are thenare mixed with a dilutant before being delivered to the machine.

In the chemical dispensing system described above, the controller isconnected to each washing machine trigger signal output and pump by adedicated line, and the controller directly activates and deactivateseach of the pumps. This arrangement, while generally satisfactory forits intended purpose, places practical limits on how many triggersignals and pumps can be connected to a single controller and creates aneed for large numbers of wires and controller input ports. Installationof these types of systems can be cumbersome since installers must keeptrack of each signal line and ensure that the each line couples theproper controller port to the proper trigger signal source or pump. Anincorrect connection may result in the wrong chemical being dispensed atthe wrong time by the system, and may not be immediately apparent,resulting in many incorrectly processed loads and resulting monetarylosses. Moreover, because the controller is merely switching the pumpson and off for an amount of time expected to provide a desired amount ofchemical to the flush manifold, the controller receives no feedbackregarding whether the pump is actually dispensing the amount of productdesired.

Chemical dispensing systems employed with commercial washing machinestypically employ peristaltic pumps to minimize both operator and systemcomponent contact with the chemical products, which are often corrosiveand toxic. Peristaltic pumps of this type include a flexible tube (orsqueeze tube) and a rotor with one or more rollers located in a pumpchamber. The one or more rollers compress a section of the squeeze tubeagainst a wall of a pump chamber, pinching off the section of squeezetube. When the rotor is rotated, the location of the pinched section ofthe squeeze tube moves along the length of the tube, thereby forcing, orpumping, fluid through the tube. The amount of fluid pumped per unittime tends to vary from pump to pump, depending on multiple variablessuch as the speed with which the rotor turns, the interior diameter ofthe squeeze tube, and the viscosity of the product being dispensed.Therefore, system installers must perform calibration measurements oneach pump so that the system controller dispenses accurate amounts ofproduct. This requirement for calibrating each pump during installationgreatly increases installation time and expense.

Squeeze tubes are also subject to wear over time from the repeatedcompression and pulling of the rollers, which causes the volume ofchemical pumped by the pump-stand to vary over time. Worn out squeezetubes must also be periodically replaced to prevent tube failure.Squeeze tube replacement can be a cumbersome endeavor, as chemicalproduct often leaks from the feed lines when the seal is broken betweenthe squeeze tube and feeder tubes. In addition to causing a loss ofproduct and undesirably exposing workers to potentially hazardouschemicals, the spilled product may also contaminate the surfaces of thesqueeze tube and pump chamber. If the chemical product is notsufficiently cleaned from these surfaces, the resulting sticky residuecan cause the roller to pull the squeeze tube through the pump chamberso that the tube becomes damaged or tangled, resulting in pump failureand further potential product spills. In addition, because thecontroller cannot determine that the pump is not dispensing the correctamount of product, any processed wash loads that rely on the failed pumpwill have to be re-processed. Further, because the timing of the pumpfailure may be difficult to determine, multiple wash loads may have tobe reprocessed.

Therefore, there is a need in the art for improved chemical dispensingsystem components and methods that more accurately and reliably controlthe dispensing of chemical products into washing machines, and thatreduce the maintenance burden and number of potential failure modesassociated with peristaltic pumps.

SUMMARY OF THE INVENTION

In a first aspect of the invention, a chemical dispensing systemcontroller includes a plurality of serial data bus interfaces that allowthe system controller to communicate with other chemical dispensingsystem components over one or more intelligent networks. To this end,the system controller may include serial data bus interfaces thatprovide communications between the system controller and a plurality ofpump controllers, machine interfaces, network gateways, as well as othersystem controllers. The system controller may also include additionalserial bus interfaces to accommodate future system expansion. Bycommunicating over serial data buses instead of using dedicatedsignaling lines, the system controller may reduce the number of physicalconnections required between the dispensing system components, therebyincreasing system reliability and reducing installation time. Theflexibility provided by digital communications over the serial databuses also provides additional advantages to the chemical dispensingsystem, such as providing support for more intelligent system componentsas well as future system improvements, the addition of new features, andsystem expansion.

To support networking functions between the system controller and thepump-stand, each pump includes a pump controller with a user selectableserial data bus address. The system controller controls the timing andamounts of chemicals dispensed to the washing machine by communicatingwith individual pump controllers connected to the pump controller serialdata bus interface using the user selectable addresses. The pumpcontroller provides several advantages to the chemical dispensingcontrol system in addition to supporting the system controllernetworking function, such as improved dispensing accuracy and pumpstatus monitoring.

In a second aspect of the invention, the pump controller may be loadedwith pump calibration data at the factory. The pump calibration data isaccessible to the pump and system controllers and is used to calculatepump run times and/or the number of pump rotor rotations necessary todeliver a desired amount of chemical product. Advantageously, by loadingpump calibration data into the pump controller at the factory, the needto perform pump-stand calibrations during installation is reduced oreliminated, thereby reducing installation time and expense.

In a third aspect of the invention, the chemical dispensing systemtracks the operational time and/or number of operational cycles on eachof the squeeze tubes installed in the pumps. Using test data regardingthe expected service life of the squeeze tube, the chemical dispensingsystem estimates the remaining service life of the tube from aging andwear based on the operational conditions (e.g., age, type of chemicalspumped, amount of chemicals pumped, etc.) experienced by the squeezetube. The chemical dispensing system may then report out the estimatedremaining tube life, as well as provide an indication to systemoperators when a squeeze tube should be replaced because the squeezetube is nearing the end of its useful service life. Tracking estimatedremaining service life may also provide additional operational benefitsand advantages to the dispensing system.

For example, to improve produce dispensing accuracy, the chemicaldispensing system may adjust pump activation periods for a specificoutput based on expected changes in pump capacity due to estimated wearand aging of the squeeze tube. To this end, the pump controller mayincrease the amount of time the pump is activated for a given amount ofproduct to be dispensed as the squeeze tube ages to compensate for anexpected reduction in pump capacity. The pump controller may therebyimprove pump dispensing accuracy over the life of the squeeze tube. Whenthe squeeze tube is replaced, the time and usage tracking in the pumpcontroller may be reset by a system operator through a user interface onthe system controller. The system controller may also provide aninterface that allows the system operator to update the pump calibrationdata based on a new pump calibration.

In a fourth aspect of the invention, the system controller controls theamount and type of chemical product dispensed by sending data addressedto the pump controller for the pump from which a desired amount ofchemical is to be dispensed. The data includes data indicative of theamount of chemical product to be dispensed, which the pump controlleruses to determine the amount of time and/or number of rotor rotationsfor which to activate the pump. The pump controller may also use storedcalibration data and/or wear data for the squeeze tube to adjust thepump activation period. In an alternative embodiment, the systemcontroller may retrieve the calibration data from the pump controllerand use the calibration data to determine an activation period for thepump. In either case, once the required activation period is determinedand communicated to the pump controller, the pump controller activatesthe pump for the determined period, thereby supplying the desired amountof chemical product to the washing machine.

Advantageously, by communicating the amount of product to be dispensedto the pump controller rather than directly activating and deactivatingthe pump, the pump may more accurately dispense the desired amount ofchemical product. More advantageously, because the pump controllercontrols activation of the pump locally, if communication is lostbetween the system controller and pump controller after activation ofthe pump (for example, due to a loose or intermittent connection), thepump controller can still dispense the desired amount of product. Thisis in contrast to a pump activated directly by a system controller,which might stop dispensing chemical product prematurely upon loss ofcommunications with the system controller, or worse yet, might continuerunning indefinitely if communications are lost between the time thepump is activated and the time the deactivation signal is sent.

To further improve the accuracy of the amount of product dispensed, thepump controller may be coupled to one or more temperature sensors thatprovide signals indicating the temperature of the chemical product thatthe pump is dispensing. Advantageously, this may improve the accuracy ofthe chemical dispensing over a range of temperatures. For example, if acontainer of chemical product that was recently delivered (or that isstored in an unheated area) is coupled to the pump, the temperature ofthe product could be substantially different from the temperature of theproduct used to calibrate the pump. To account for the effect ofviscosity on the amount of product dispensed, the pump controller mayuse information regarding the temperature of the product to calculatethe viscosity of the product, and adjusts pump activation periodsaccordingly.

In a fifth aspect of the invention, each pump controller may include adetection circuit that allows the pump controller to determine if theproduct container to which it is coupled is running low on product. Tothis end, the pump controller may include ports which may be coupled toproduct level probes that provide signals indicative of the amount ofchemical product left in a product container coupled to the pump. Inresponse to sensing that the product is running low, the pump controllermay activate local alarms (such as a flashing LED or buzzer) and/orcommunicate the product level condition to the system controller overthe serial data bus. In response to receiving a low level productcondition message from the pump controller, the system controller mayalso activate a local alarm, and/or send an alarm message to the systemoperator through a network gateway.

To provide an out of product indication to the system, the pumpcontroller may begin tracking the amount of chemical product dispensedbeginning from the time at which a low level indication is received froma product level probe. If the low level indication is not cleared byrefilling or replacing the container before a predetermined amount ofadditional product is dispensed, the pump controller may stop activatingthe pump and inform the system controller that the product has run out.Advantageously, this allows the chemical dispensing system to keepoperating up until the point where a chemical product is about to runout, but prevents the system from operating without sufficient chemicalproduct to properly process wash loads.

In an alternative embodiment, the pump may include an integratedout-of-product detection capability. This integrated out-of-productdetection capability includes conductive plastic inserts in the flowpath of the product so that the conductive plastic inserts are incontact with product passing through the pump. The conductive plasticinserts are electrically coupled to the detection circuit in the pumpcontroller. The detection circuit is sensitive to the impedance betweenthe inserts so that when product is present in the line between theinserts, the impedance presented causes the detection circuit to providean indication to the pump controller that product is present. However,when product is not present in the line, such as if the pump beginsdrawing air from an empty chemical product container, the impedancebetween the conductive plastic inserts increases. This increase inimpedance between the conductive plastic inserts, in turn, causes thedetection circuit to provide an indication to the pump controller thatthe chemical product has run out. In response, the pump controller stopsactivating the pump and informs the system controller that the producthas run out. Advantageously, this provides an additional mechanism thatprevents the chemical dispensing system from operating when a chemicalproduct has run out, thereby preventing the system from operating whenthere is insufficient chemical product to properly process wash loads.The pump controller may also activate local or remote alarms indicatingan out product condition so that the condition is brought the attentionof the system operator.

The system controller may include a selectable alarm notificationfeature that allows the system operator to select the types of alarmsthat are activated, as well as the time and duration of the alarms,based on the condition causing the alarm. Advantageously, this featureallows the system operator to customize the type of notification basedon the perceived severity of the alarm. For example, alarms caused byconditions that do not immediately affect the performance of the system(such as low level alarms) may be logged in a productivity reportmaintained by the system controller, or could trigger a notificationmessage sent through the network gateway to an e-mail address. Othermore severe alarms (such as out of product alarms) may be configured toprovide a more urgent indication, such as audible indicators (e.g., abuzzer) and/or visual indicators (e.g., a strobe light) at the systemcontroller and/or pump-stand location.

In a sixth aspect of the invention, the pump controller provides aselectable flush manifold status monitoring feature. To this end, thepump controller includes an electrical input port that is operativelycoupleable to one or more sensors in the flush manifold. The sensors(e.g., a flow switch) provide an indication of whether the flushmanifold is ready to receive a dispensed chemical product. If the flushmanifold is not ready to receive the dispensed chemical (e.g., the flowswitch signal indicates that there is insufficient flow of diluentthrough the flush manifold), the pump controller refrains fromactivating the pump, and provides local and/or remote alarmnotifications indicating the problem encountered.

In seventh aspect of the invention, the pump includes a pump chamber lidinterlock system. The interlock system includes a sensor that provides asignal to the pump controller indicating the position of the pumpchamber lid. For example, a magnet located in the pump chamber lid and aHall Effect sensor located in the pump housing. In response to receivinga signal indicating that the pump chamber lid is open, the pumpcontroller disables the pump. Advantageously, the pump chamber lidinterlock system may thereby prevent injuries from pinched fingers anddamage to the pump that may result if the pump is activated while asystem operator is, for example, replacing a squeeze tube.

In an eighth aspect of the invention, the pump includes a housing thatincludes integral input and output channels and a motor having ahorizontal orientation. The input channel, and the output end of thesqueeze tube is coupled to a product delivery line by the integraloutput channel. The squeeze tube is thereby isolated by the pump housingfrom mechanical forces present on the supply lines. The squeeze tube isfluidically coupled to the input and output channels by 90 degree elbowsso that the squeeze tube is oriented in a horizontal orientation. The 90degree elbows are free to pivot inside the integral channels, andthereby allow axial motion at the ends of the squeeze tube. This axialmotion is believed to further reduce mechanical stresses on the squeezetube when the pump rotor is in motion, potentially extending squeezetube service life. The 90 degree elbows also facilitate removal andreplacement of the squeeze tube by allowing the squeeze tube to be in ahorizontal position at a high point in the chemical product supply path.Gravity thus urges the chemical product to retreat back into the supplylines when the squeeze tube assembly is removed, reducing the likelihoodof a spill.

The horizontal orientation of the motor facilitates positioning therotor in a proper relationship with the horizontally oriented squeezetube, and improves pump packaging. In an embodiment of the invention,the integral input and output channels are located in a back side of thepump housing so that the supply lines are positioned out of the way, andto facilitate use of European industry standard DIN rail system tosecure the pumps comprising the pump stand to a vertical surface, suchas a wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description given below, serve to explain the invention.

FIG. 1 is an illustration of an exemplary chemical dispensing systemincluding a system controller, pump-stand, and machine interface.

FIG. 2 is a schematic diagram of the chemical dispensing system in FIG.1 illustrating the interconnectivity between the system controller,machine interface, pumps, washing machine, and chemical productcontainers in an embodiment of the invention where the system controllerlocated with the washing machine.

FIG. 3 is a schematic diagram of the chemical dispensing system in FIG.2 with the system controller relocated to the pump-stand.

FIG. 4 is a schematic illustrating details of the system controller.

FIG. 5 is a schematic illustrating details of the pump including a pumpcontroller and motor, as well as sensors and indicators associated withoperation of the pump controller.

FIG. 6A is a detailed schematic of a detection circuit shown in FIG. 5including an oscillator with an input coupled to a probe assembly.

FIG. 6B is a schematic of the detection circuit in FIG. 6A with a highimpedance being provided by the probe assembly showing the oscillator inan oscillating state.

FIG. 6C is a schematic of the detection circuit in FIG. 6A with animpedance being provided by the probe assembly that causes theoscillator to be in a different state to include a non-oscillatingstate.

FIG. 7 is a schematic illustrating additional details of the machineinterface presented in FIGS. 1-3.

FIG. 8 is an isometric view of the pump illustrating features of thepump housing and pump components.

FIG. 9 is a cross-sectional diagram of the pump in FIG. 8 illustratingthe integral input and output channels.

FIG. 10 is a top view of the pump illustrating the squeeze tube, rotor,and pump chamber.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the sequence of operations as disclosedherein, including, for example, specific dimensions, orientations,locations, and shapes of various illustrated components, will bedetermined in part by the particular intended application and useenvironment. Certain features of the illustrated embodiments have beenenlarged or distorted relative to others to facilitate visualization anda clear understanding. In particular, thin features may be thickened,for example, for clarity or illustration.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention provide a networked control system fordispensing chemical products in commercial washing machine applicationsthat assists in overcoming the difficulties with contemporary chemicaldispensing systems. In an embodiment of the invention, a systemcontroller serves as a master controller and is linked via a pluralityof serial data buses the other system nodes. The serial data businterfaces provide an increased communications capability between thesystem controller and the system nodes as compared to conventionalsystems. The serial data buses thereby support adding intelligence tosystem nodes so that control functions may be distributed among thesystem nodes rather than concentrated in the system controller. By wayof example, each pump controlled by the system includes a pumpcontroller, which enables chemical product dispensing to be controlledlocally in each pump based on commands received from the systemcontroller over the serial data bus.

The serial data bus network allows the system controller to query theoperational status of each of the other system components (such as amachine interface or any of a plurality of pump-stands) to determine ifthe system is ready to dispense chemicals before issuing commands. Theserial data bus also provides power to network components so thatadditional nodes may be added to the network by simply daisy-chaining anew node to an existing node. This allows, for example, an additionalpump to be added to an existing group of pumps comprising a pump-standby merely coupling the new pump to the end of the chain of pumps with ajumper.

The system controller provides a user interface, stores processformulas, and displays system alarms and status indicators, as well asserving as the master controller for the serial data busses. To dispensechemical products according to a stored formula (e.g., a productdispensing profile for a particular process), the system controllersends data to one or more the pumps indicting the amount of chemicalproduct that the pump stand is required to dispense. The systemcontroller also periodically interrogates the pumps to verify that thepumps are operating properly. To this end, the system controller willtypically query the status of a network node before issuing a command.The system controller may thereby obtain positive verification that thenode is operating properly before issuing a command. The systemcontroller may also include a serial data port configured to communicatewith an optional network gateway. When present, the network gatewayprovides a data link between the system controller and an outsidenetwork, such as the Internet, so that system operators may communicatewith one or more system controllers from a remote location.

To support the serial data bus network, each pump-stand includes a pumpcontroller that provides local control of the pump motor and enables adata link process with the system controller. To this end, the pumpcontroller includes a user selectable address that allows the systemcontroller to address each pump controller individually over the sharedserial data bus. The pump controller provides intelligence to the pumpthat supports more accurate dispensing of chemical product based onstored calibration data, monitoring and reporting of pump status,chemical product level monitoring, control of flush manifold operation(if present), and transmission of alarms to the system controller.

Referring now to the drawings, FIGS. 1-3 illustrate an exemplarychemical dispensing system 10 shown in two typical deploymentconfigurations with a washing machine 11, which may be a laundrymachine, a ware-wash machine, a healthcare wash, or any other type ofmachine that uses dispensed chemicals. One of ordinary skill in the artwill recognize that this system 10 is only for illustration purposes andthat embodiments of the invention may be used with other configurationsof the chemical dispensing system 10. The base configuration of thechemical dispensing system 10 includes a system controller 12 coupled toa plurality of pumps 14 a-14 c comprising pump-stand 15 by a pump serialdata bus 16. For illustrative purposes, FIGS. 1-3 show a system with 3pumps 14 a-14 c. However, it is understood that other numbers of pumpsmay be used, and the invention is not limited to any specific number ofpumps. The pumps 14 a-14 c each include a pass-through serial data busconnector 18 (FIG. 5) so that the pumps 14 a-14 c may be connected in adaisy-chain configuration on the pump-stand 15. Each pump 14 a-14 c isthereby connected to an adjacent pump by a jumper 22 so that the pumps14 a-14 c are each electrically coupled to the pump serial data bus 16.The pump serial data bus 16 thus includes multiple jumpers 22 andpass-through connectors 18. In an embodiment of the invention, jumpers22 may be comprised of a printed circuit board (PCB) encapsulated inplastic to facilitate quick connections between pumps 14 a-14 c andpower supply 20.

System power is supplied by a power supply 20 mounted to the pump-stand15 near one end of the chain of pumps 14 a-14 c. The power supply 20 maybe coupled to the pump serial data bus 16 by connecting the output ofthe power supply 20 to one end of the pass-though connector 18 in theend pump, shown here as the left most pump 14 a. The power supply 20 isthereby coupled to the pumps 14 a-14 c and the system controller 12 bythe serial data bus 16. In a preferred embodiment, the pumps 14 a-14 c,and power supply 20 may be mounted to a DIN rail 28 on the pump stand15, although the invention is not so limited, and other mountinglocations and methods may be used.

To obtain data concerning the operational status of the washing machine11, the system controller 12 is coupled to a machine interface 24 by amachine interface serial data bus 26. Typically, the system controller12 will be located near (or mounted to) the washing machine 11 as shownin FIGS. 1 and 2, but the system controller 12 may also be locatedremotely from the washing machine 11 as shown in FIG. 3. For example, inthe alternative embodiment illustrated in FIG. 3, the system controller12 is mounted to the DIN rail 24 so that the system controller 12, pumps14 a-14 c and power supply 20 are all affixed to the pump-stand 15 bythe DIN rail 28.

The pump-stand 15 is configured to provide product to the washingmachine 11 from various chemical storage containers 30, 32, 34, each ofwhich is fluidically coupled to one of pumps 14 a-14 c by a productsupply line 36. Typically, the output of each pump 14 a-14 c isfluidically coupled to a flush manifold 42 by flush manifold supplylines 44 as shown in FIGS. 1-3. However, the pumps 14 a-14 c may also befluidically coupled directly to the washing machine 11 so that undilutedproduct is delivered to the machine 11. In embodiments including theflush manifold 42, an output of the flush manifold 42 is coupled to thewashing machine 11 by a machine supply line 45, and an input of theflush manifold 42 is coupled to a diluent source 46 by a diluent valve48. The diluent valve 48 may be electrically coupled to one or more ofthe pumps 14 a-14 c, (FIG. 5) so that the chemical dispensing system 10can control delivery of product to the washing machine 11 by regulatingthe flow of diluent through the flush manifold 42.

The power supply 20 is typically mounted on the DIN rail 28 next to apump 14 a-14 c, although other mounting locations may be used. The powersupply 20 is connected to source of AC line voltage (not shown) andprovides a DC voltage (such as to 24 VDC) suitable for powering systemcontroller 12, pumps 14 a-14 c, and machine interface 24. When mountedon the DIN rail 28, the power supply 20 will typically be coupled toeither the left side of pass-through connector 18 of rightmost pump 14a, (as shown); or to the right side of pass-through connector 18 of theleftmost pump 14 c. Power is thereby distributed to the systemcontroller 12 and pumps 14 a-14 c via the serial data bus 16. To thisend, the serial data bus 16 may include power and ground conductors, aswell as one or more data conductors. In an embodiment of the invention,the pump serial data bus 16 includes a power conductor, a groundconductor, a positive data conductor, and a negative data conductor. Thedata conductors thereby form a balanced, or differential, serial datatransmission line. The system controller 12, in turn provides power tothe machine interface 24 over the machine interface serial data bus 26,which is typically configured to have the same conductor layout as thepump serial data bus 16. Advantageously, the pass-through connectors 18and pump serial data bus configuration make adding additional pumps tothe pump-stand 15 a simple process, thereby facilitating the addition ofadditional chemical products to the chemical dispensing system 10.

Some embodiments of the invention may also include probe assemblies 50operatively disposed in containers 30, 32, 34. The probe assemblies 50,in turn, may be electrically coupled to a detection circuit 52 (FIG. 5)in the pump 14 a-14 c that dispenses product from the container 30, 32,34 in which the probe assembly 50 is located. Probe assemblies 50 may beconfigured to provide a signal to the detection circuit 52 indicative ofthe level of product in the container 30, 32, 34 so that the pumps 14a-14 c may monitor product levels in their associated containers 30, 32,34. Probe assemblies 50 are known in the art and typically include oneor more conductive probes that present different impedances to thedetection circuit 50 depending on whether the probe assembly 50 is incontact with product. Suitable probe assembles and detection circuitsare described in U.S. patent application Ser. No. 13/164,878, entitled“System and Method for Product Level Monitoring in a Chemical DispensingSystem”, Attorney Docket No. NOVC-23, the disclosure of which isincorporated herein by reference in its entirety.

Referring now to FIG. 4 and in accordance with an embodiment of theinvention, the system controller 12 includes a processor 54, memory 56,an input/output (I/O) interface 58, a user interface 60, a systemcontroller voltage supply circuit 62, and a machine interface powersupply output circuit 64. The I/O interface 58 is communicativelycoupled to the processor 54 and employs a suitable communicationprotocol for communicating with the serial data busses, and. Theprocessor 54 may thereby communicate through the I/O interface 58 to themachine interface 24 via the machine interface serial data bus 26, thepumps 14 a-14 c (shown as a single pump for purposes of illustration)through pump serial data bus 16, and a network gateway 68 via a networkgateway serial data bus 70. The system controller 12 may also includeone or more additional serial data bus interfaces 72 to accommodatefuture system expansion. The serial buses may be connected to the I/Ointerface 58 (as well as the various network nodes) though serial businterfaces, each of which includes a suitable multi-pin connector 74.

Processor 54 may be a microprocessor, microcontroller, programmablelogic or any other suitable device that manipulates signals based onoperational instructions, which may be stored in memory 56. The memory56 may be a single memory device or a plurality of memory devicesincluding but not limited to read-only memory (ROM), random accessmemory (RAM), volatile memory, non-volatile memory, static random accessmemory (SRAM), dynamic random access memory (DRAM), flash memory, cachememory, and/or any other device capable of storing digital information.The memory 56 may also be integrated with the processor 54.

The processor 54 executes or otherwise relies upon computer programcode, instructions, or logic (collectively referred to as program code)to execute the functions of the system controller 12. To this end, asystem controller application 66 may reside in memory 56 and may beexecuted by the processor 54. The system controller application 66controls and manages the chemical dispensing system 10 by communicatingwith other system components via the I/O interface 58 and serial databuses 16, 26, 70. The system controller application 66 may therebyobtain information regarding the operational status of the washingmachine 11 from the machine interface 24, and in response, causes thepumps 14 a-14 c to dispense chemicals in a controlled way.

The user interface 60 may be operatively coupled to the processor 54 ofthe system controller 12 in a known manner. The user interface 60includes output devices, such as alphanumeric displays, one or moretouch screens, light emitting diodes (LEDs), acoustic transducers,and/or any other suitable visual and/or audio indicators; and inputdevices and controls, such as the aforementioned touch screen, analphanumeric keyboard, a pointing device, keypads, pushbuttons, controlknobs, etc., capable of accepting commands or input from the systemoperator and transmitting the entered input to the processor 54. Theuser interface 60 thereby provides a mechanism by which the systemoperator may enter new washing process formulas, set and/or deactivatealarms, update calibration data, retrieve and view system data (such asamounts of product dispensed and number and type of wash loads run) andotherwise operate and manage the chemical dispensing system 10.

The system controller voltage supply 62 receives power from the powersupply 20 via the pump serial data bus 16. The system controller voltagesupply may contain circuits, such as voltage regulators, that conditionand adjust the voltage received from the power supply 20, therebyproviding suitable voltages for running the processor 54 and othersystem controller components. The machine interface power supply outputcircuit 64 may receive power from the system controller voltage supply62, or directly from the power supply 20 via the pump serial data bus16. The machine interface power supply circuit 64 may condition thepower before transmitting it to the machine interface 24; or the machineinterface power supply circuit 64 may merely pass the power receivedfrom the power supply 20 on to the machine interface 24 over the machineinterface serial data bus 26 without significant alteration.

The network gateway 68 may be a computer equipped to provide aninterface between the system controller 12 and an external network 76,such as the Internet. To this end, the network gateway 68 may include anetwork gateway application running on a processor that performsprotocol translation, converts data rates, and/or provides any otherfunctions necessary to provide interoperability between the chemicaldispensing system and the external network. The network gateway 68 maythereby allow computers or other communication devices that are attachedto the external network 76 to communicate with the system controller 12so that system operators may remotely control and monitor the chemicaldispensing system 10. The network gateway 68 may also be configured toaddress multiple system controllers 12 over a single network gatewayserial data bus 70.

Referring now to FIGS. 5 and 6A-6C, each pump 14 a-14 c includes a pumpcontroller 78 in communication with a motor 80. The pump controller 78may also be in communication with the detection circuit 52, internal andexternal temperature sensors 82, 84, a plurality of status indicatorLEDs 86, a local alarm buzzer 88, a mute switch 90, a flow sensor 96, apump chamber lid sensor 98, address selector switch 99, pump primeswitch 101, and a valve driver circuit 103. The pump controller 78 mayalso include a pump controller voltage supply 105 that provides suitablevoltage levels for running the controller components. The motor 80 maybe a brushless direct current (BLDC) electric motor coupled to a rotor100 by a transmission 102. The rotor 100 includes one or more rollers104 and is positioned in a pump chamber 106 with a squeeze tube 108. Therotor 100, pump chamber 106, and squeeze tube 108 are further configuredso that when torque is applied to the rotor 100 by the motor 80, therotor 100 rotates in such a way that the rollers 104 compress thesqueeze tube 108 against a side wall of the pump chamber 106 in aprogressive fashion that causes fluid to be urged through the squeezetube 108.

So that the pump 14 a-14 c may dispense product, one end of the squeezetube 108 is coupled to an integral input channel 110, and the other endof the squeeze tube 108 is coupled to an integral output channel 112.The integral input and output channels 110, 112 are in turn fluidicallycoupled to the product supply and flush manifold supply lines 36, 44,respectively. Activating the motor 80 thereby causes fluid to be drawninto the squeeze tube 108 from the product supply line 36 via theintegral input channel 110 and expelled into the flush manifold supplyline 44 via the integral output channel 112. Product may thereby beconveyed from the product container 30, 32, 34 to the flush manifold 42by pumps 14 a-14 c.

Similarly as described with respect to the system controller 12, thepump controller 78 includes a processor 114, memory 116, and an I/Ointerface 118 that provides a communications link between the pumpcontroller processor 114 and the pump serial data bus 16 via thepass-through connector 18. The pump controller processor 114 may befurther operatively coupled to detection circuit 52, motor 80, internaland external temperature sensors 82, 84, status indicator LEDs 86, localalarm buzzer 88, mute switch 90, flush manifold flow sensor 96, pumpchamber lid sensor 98, address selector switch 99, pump prime switch101, and valve driver circuit 103.

Memory 116 may contain a pump controller application 120 comprised ofprogram code that, when executed by the processor 114, causes the pumpcontroller 78 to provide local motor control and support a data linkprocess that allows the system controller 12 and pump controller 78 tocommunicate over the pump serial data bus 16. The address selectorswitch 99 may be any suitable switch, such as a rotational selectorswitch or dip switch that is accessible from the outside of the pump 14a-14 c. Advantageously, the address selector switch 99 thereby providesa quick and easy means to visually identify the current address of eachpump controller 78 in the network.

Each pump controller 78 that is sharing the pump serial data bus 16 hasa unique address that is set on the address selector switch 99 prior toapplying power to the pumps 14 a-14 c. The pump controller application120 reads the address selector switch at power up and loads the networkaddress into memory 116. Once the pump controller application 120 hasloaded the network address into memory, the network address will remainfixed so long as the pump controller 78 is under power. Advantageously,this feature reduces the risk of the pump controller's network addressbeing changed inadvertently while the system 10 is in operation, whichcould result in more than one pump controller 78 having the same networkaddress. To change the network address of the pump controller 78, thesystem operator must power down the pump stand 15, change theconfiguration of the address selector switch 99, and reapply power sothat the new address is loaded by the pump controller application 120.

The pump prime switch 101, when enabled, provides an automated pumppriming function. To prevent inadvertent activation of the primingfunction, the operation of the pump prime switch 101 may have to beenabled in the system controller 12 through a password protected menuaccessed through the system controller user interface 60. Enabling thepump prime function in the system controller 12 causes the systemcontroller application 66 to set a priming feature enable flag in thepump controller 78. In response to sensing that the pump prime switch101 has been activated, the pump controller application 120 checks thepriming feature enable flag. If the flag is set, the pump controllerapplication 120 activates the motor 80 for a sufficient amount of timeto ensure that the supply lines 36, 44 and pump 14 a-14 c are primedwith product. In contrast, if the feature enable flag is not set, thepump controller application 120 may simply ignore the state of the pumpprime switch 101.

The pump chamber lid sensor 98 provides a signal indicative of theposition of a pump chamber lid 178 (FIG. 9) to the processor 114. Tothis end, the lid sensor 98 may include a magnet 122 and a Hall Effectsensor 124 configured to provide a first signal to the processor 114when the lid 178 is in an open position, and a second signal to theprocessor 114 when the lid 178 is in a closed position. To reduce therisk of damage to the pump 14 a-14 c as well as injury to the systemoperator, the pump controller application 120 checks the pump chamberlid sensor signal before activating the motor 80. If the signalindicates that the pump chamber lid 178 is in a closed position, thepump controller application 120 will activate the motor in the normalmanner. However, in response to a signal indicating that the pumpchamber lid 178 is in an open position, the pump controller application120 may disable the motor 80 as well as provide an indication to thesystem controller 12 that the motor 80 is not in a condition to beactivated.

The detection circuit 52 supports a low level detection feature, whichmay be enabled in the pump controller application 120 by activating thefeature through the system controller user interface 60. The detectioncircuit 52 includes in input port coupleable to the probe assembly 50through a probe assembly connector 126, which may be located on thebottom of the pump 14 a-14 c. The detection circuit 52 includes a lowfrequency oscillator that includes an active element, or oscillator 128(FIGS. 6A-6C) and a load element 130. The oscillator 128 may include aCMOS inverter or any other suitable device capable of producing anoscillation when coupled to load element 130. Load element 130 may be aresistor-capacitor (RC) circuit or some other suitable circuit thatprovides a suitable load or feedback to the oscillator 128 to cause theoscillator 128 to oscillate. The detection circuit 52 produces anoscillation when a high impedance electrical load is present on theinput to the probe assembly connector 126, such as an electrical loadwith an impedance greater than 5 megohms. The detection circuit 52thereby provides a low frequency oscillation signal when the qualityfactor of the oscillator 128 is sufficiently unaltered by the electricalload from a probe assembly 50 that is not in contact with a monitoredproduct. When an electrical load that has a high impedance is coupled tothe input 126, the oscillator 128 comprising detection circuit 52 istuned to oscillate at a nominal operating frequency, such as about 10Hz, for example. The pump controller application 120 may therebydetermine if there is sufficient product remaining to contact the probeassembly 50 by monitoring the output of the detection circuit 52 for anoscillation.

A pair of conductive probes 132, 134 comprising the probe assembly 50may be connected to the detection circuit 52. The probe assembly 50 isconnected across the input 126 of the detection circuit 52 so that oneprobe 132 is connected to one side of load element 130 and the otherprobe 134 is connected to the other side of load element 132, which mayalso be coupled to a reference ground 136. When the probe assembly 50 issuspended in air, such as when the product in the monitored container30, 32, 34 has dropped below the probe assembly 50, the impedance of theprobe assembly 50 as seen by the detection circuit 52 has a low loadingeffect on the oscillator 128. The quality factor of the oscillator 128is thus relatively unaffected by the presence of the probe assembly 50so that the detection circuit 52 outputs a time varying voltage signalat the nominal frequency as illustrated in the schematic diagram of FIG.6B.

However, when one or both of the probes 132, 134 are in contact with aconductive solution, an impedance 138 from the probes 132, 134 is seenby the detection circuit 52. A typical impedance between the probes 132,134 when in contact with product will be between 10 kilohms and 1megohms. The impedance 138 will lower the quality factor of theoscillator 128, which changes the operating parameters of the oscillator128 due to the parallel loading effect of the probe assembly 50. Thesechanged parameters will cause the oscillator 128 to oscillate at afrequency different from the nominal frequency or to cease oscillatingdepending on the load presented by the probe assembly 50, as illustratedin the schematic diagram of FIG. 6C. Thus, in response to being coupledto a probe assembly 50 that is in contact with product, the detectioncircuit 52 will output a signal having a different frequency or thatstops varying altogether, such a constant voltage at ground potential.This change in the output of the detection circuit 52 thereby providesan indication to the processor 114 of the presence or absence of productat the probe assembly 50.

The status indicator LED's 86 may include a first LED that provides avisual indication that the pump 14 a-14 c is powered, a second LED thatprovides an indication of the presence of data traffic on the pumpserial data bus 16, a third LED to indicate if a local error is active,and a fourth alarm LED that provides an indication of the level ofproduct detected by the pump controller application 120. The power anddata traffic status indicator LEDs may be coupled to and activated bythe processor 114, or may be directly tied to a pump power supply and/ordata lines as the case may be. The alarm LED may be used to indicate avariety of conditions. By way of example, the pump controllerapplication 120 may cause the alarm LED to flash when a probe assembly50 is coupled to the detection circuit and the product level feature isactive to provide an indication of such to the system operator. Inresponse to detecting a low product condition, the pump controllerapplication 120 may cause the alarm LED to be illuminated continuouslyso that the system operator is provided with a visual indication of thelow product level condition.

The pump controller application 120 may also be configured to activatethe local alarm buzzer 88 in response to detecting a low product levelcondition. The system operator may cause the pump controller application120 to silence the alarm buzzer 88 by pressing mute switch 90. In someembodiments, the pump controller application 120 may send an alarmmessage to the system controller 12 in response to a status query sothat the system controller 12 may activate an alarm or otherwise reportto the system operator that an alarm condition exists at the pump-stand15. The pump controller application 120 may be configured to providedifferent mute responses depending on how long or how many times themute switch 90 is activated. By way of example, in some embodiments ofthe invention, the first time the mute switch 90 is pressed, the alarmmight be silenced for a short period, such as an hour. If the muteswitch 90 is held down for a length of time, such as 3-4 seconds, thealarm might be silenced for a longer period, such as a weekend. Toprovide an indication that the local alarm buzzer 88 has been muted, thelocal alarm LED may be made to flash at a slower rate than normal. Therate of flashing may be further adjusted so that the local alarm LEDflashes at a slower rate when a long duration alarm silencing period hasbeen activated (such as a weekend) than when a short duration silencingperiod has been activated (such as an hour).

The pump-stand 15 may be configured to deliver product directly to thewashing machine 11, or the product may be dispensed into the flushmanifold 42 and delivered to the machine 11 by a diluent, which is theconfiguration illustrated in FIGS. 1-3. When the pump-stand 15 isdeployed with flush manifold 42, a flush-flow control feature may beactivated in the pump controller application 120 of at least one of thepumps 14 a-14 c associated with the system controller 12. As with theprevious optional features, the flush-flow feature is activated in thepump controller application 120 through the user interface 60 of thesystem controller 12. Typically, the flush flow feature is onlyactivated in one pump 14 a-14 c per pump-stand 15, with the systemcontroller 12 controlling the flush manifold 42 by addressing flushmanifold related commands to the pump controller 78 that is coupled tothe diluent valve 48. In order to provide sufficient drive current andvoltages to the diluent valve 48, the processor 114 may be coupled tothe diluent valve 48 by a valve circuit driver 103. In cases where thevalve circuit driver 103 is not coupled to the diluent valve 48, thevalve circuit driver output port 140 may be used to provide a switchedvoltage output, such as a 24 VDC switched output, for activatingexternal alarms or other uses.

The pump controller application 120 may also monitor the flow sensor 96,which provides a signal indicative of the rate that diluent is flowingthrough the flush manifold 42. The pump controller application 120 maythereby make determinations concerning the dispensing of product intothe flush manifold 42 based on whether there is sufficient diluent flowto deliver the product to the washing machine 11. The pump controllerapplication 120 may also report alarm conditions to the systemcontroller 12 if the detected diluent flow rate deviates from anacceptable level.

Referring now to FIG. 7, the machine interface 24 includes a processor142 that is operatively coupled to a memory 144, an I/O interface 146, atrigger signal interface 148, and a display 150. A machine interfacevoltage supply 152 is coupled to and receives power from the machineinterface serial data bus 26, and includes voltage regulation circuitsthat provide suitable voltages to the circuits comprising the machineinterface 24. The trigger signal interface 148 is coupled to triggersignals in the washing machine 11 by optical isolators 154 a-154 n,which provide galvanic isolation between the high voltage triggers inthe washing machine 11 and the other chemical dispensing systemcomponents. In an embodiment of the invention, there may be 10 triggersignals, with each signal being coupled to the trigger signal interfaceby an optical isolator 154 a-154 n.

Memory 144 may contain a machine interface application 156 comprised ofprogram code that, when executed by the processor 142, causes themachine interface 24 to determine the operational state of the washingmachine 11 based on machine trigger signals detected by the processor142 via the trigger signal interface 148. The machine interfaceapplication 152 may also handle the networking and messaging functionsrequired to communicate with the system controller 12 over the machineinterface serial data bus 26. To this end, the I/O interface 146 mayemploy a suitable communication protocol for communicating over themachine interface serial data bus 26. In an embodiment of the invention,the machine interface 24 is configured as a slave module, and will onlyrespond back to the system controller 12 in response to being queried bythe system controller 12.

The trigger signal interface 148 works cooperatively with opticalisolators 154 a-154 n to convert the local high voltage trigger signalsreceived from the washing machine 11 into signals suitable for couplingto the processor 144. The machine interface application 156 determinesthe state of the washing machine 11 based on the detected triggersignals, and may store time stamped trigger signals in memory 144 forlater use and reporting. In response to a query from the systemcontroller 12, the machine interface application 152 communicates thedetermined state of the machine 11 and/or detected triggers to thesystem controller application 66. In response to the washing machinestate (e.g., beginning wash cycle), the system controller application 66may, in turn, cause the pump controller application 120 to dispenseproduct to the washing machine 11 (e.g., dispense 100 milliliters ofdetergent). The machine interface display 150 may include an electronicmembrane overlay having LEDs that are illuminated by the machineinterface application 156 to indicate the particular triggers that havebeen detected and qualified. The display 150 may also include anadditional LED that is illuminated to indicate the presence of datatraffic on the machine interface serial data bus.

With reference to FIGS. 8-10, in which like reference numerals refer tolike features in FIGS. 1-7 and in accordance with an embodiment of theinvention, the representative pump 14 a-14 c includes a housing 158having a pump chamber 106, an integral input channel 110, and anintegral output channel 112. The rotor 100 and squeeze tube 108 arepositioned in the pump chamber 106, and the rotor 100 includes rollers104 configured to compress the squeeze tube 108 against a sidewall 160of the pump chamber 106. The squeeze tube 108 has a first end coupled tothe integral input channel 110 by an inlet fitting 162 and a second endcoupled to the integral output channel 112 by an outlet fitting 164. Theinlet and outlet fittings 162, 164 include a 90 degree elbow so that thesqueeze tube 108 is oriented in a plane perpendicular to the integralinput and output channels 110, 112. Each fitting 162, 164 includes upperand lower o-rings 166, 168 that provide a fluid-tight seal between thefitting 162, 164 and its respective integral channel 110, 112.Advantageously, the o-rings 162, 164 allow the fittings 162, 164 topivot axially, which may reduce lateral bending forces on the squeezetube 108 at the squeeze tube/fitting connection points.

The pump controller 78 and associated circuits are mounted in a lowercavity 170 near the bottom of the pump housing 158 to facilitate accessto the various electrical connectors associated with the pump controller78. The pump motor 80 and transmission 102 are stacked vertically in acentral cavity 172, so that the motor 80 has a horizontal orientation.The transmission 102 may provide speed and torque conversion between themotor 80 and rotor 100 so that the rotor rotates at a desirable speed.In an alternative embodiment of the invention, the transmission 102 maybe omitted and the motor 80 directly coupled to the rotor 100. The motor80 may be a brushless DC motor, and may include an integrated motorcontroller (not shown) that provides signals indicative of the motorspeed in rotations per minute to the pump controller processor 114.Advantageously, the integrated motor controller thereby allows the pumpcontroller application 120 to determine and report motor status (such asa locked rotor condition) as well as precisely measure product volumedispensing by tracking the speed and/or number of rotations of the rotor100.

The product and flush manifold supply lines 36, 44 are coupled to theintegral input and output channels 110, 112 by plastic inserts 174, 176,respectively. Plastic inserts 174 and 176 may include a threaded upperend configured to engage the lower ends of the integral input and outputchannels 110, 112. The plastic inserts 174, 176 each include a barbedlower end that provides a fluid tight seal when coupled to the productand flush manifold supply lines 36, 44. In an embodiment of theinvention, the plastic inserts 174, 176 may be comprised of a conductiveplastic, such as carbon impregnated polypropylene. In this alternativeembodiment, the conductive plastic inserts 174, 176 may be electricallycoupled to the detection circuit 52 and thereby serve as integratedconductive probes 132, 134 that provide an out-of-product indication tothe detection circuit 52.

The pump chamber lid 178 may be comprised of transparent plastic thatallows system operators to view the operation of rotor 100 and squeezetube 108. The magnet 122 is positioned within the pump chamber lid 178so that when the lid 178 is closed, the magnet 122 causes the HallEffect sensor 124 to change its output, indicating to the pumpcontroller application 120 that the pump chamber lid 178 is in a closedposition. When the pump chamber lid 178 is opened, the change themagnetic field in the region of the Hall Effect sensor 124 causes theHall Effect sensor to provide a signal to the pump controllerapplication 120 that indicates the lid 178 is not closed. In response,the pump controller application 120 may disable the motor 80 to reducethe risk of injury to system operators and/or damage to the squeeze tube108 from fingers or other objects becoming entangled with the rotor 100.

In operation, the system controller 12 may be configured as a master,and the machine interface 24 and pump controllers 78 configured asslaves. Using this master/slave configuration, the machine interface 24and pump controllers 78 only communicate with the system controller 12in response to a query or other message from the system controller 12.This master/slave arrangement thus ensures that only one system nodetransmits data over their associated serial data bus at a time. Processformulas are programmed into the system controller 12 over the userinterface 60, and the system operator selects which chemical dispensingprocess formula the system controller 12 will implement based on thetype of load the washing machine 11 is processing. The system controller12 is thus the master controller in the network and handles all of theprocess formulas and any required mathematical calculations, as well asproviding a human-machine interface to the chemical dispensing system10.

Operations in the chemical dispensing system 10 are initiated by thesystem controller 12 querying the status of the machine interface 24. Tothis end, the system controller application 66 sends a status querymessage to the machine interface 24 over the machine interface data bus26. The machine interface application 156 responds to the status querymessage with a status update that includes data regarding any qualifiedtriggers that have been logged by the machine interface 24 since thelast query message the system controller 12. In response to the contentof the machine controller response message, the system controllerapplication 66 determines the state of the washing machine 11. Based onthe state of the washing machine 11 and the process formula selected bythe system operator, the system controller application 66 furtherdetermines which product, if any, needs to be dispensed as well as howmuch of the product should be dispensed. All pump operations are thusultimately dependent on the qualified triggers, which are processedlocally by the machine interface 24 and sent to the system controller 12by the machine interface 24 when prompted.

If the washing machine 11 is in a state requiring product to bedispensed (e.g., beginning a wash load), the system controllerapplication 66 queries the status of the pump 14 a-14 c associated withthe container 30, 32, 34 holding the product to be dispensed. To thisend, the system controller application 66 sends a query messageaddressed to the pump controller 78 associated with the product to bedispensed over the pump serial data bus 16. The pump controllerapplication 120 responds to the query message by reporting back pumpstatus, including any out of product or other system alarms, which (ifpresent) are displayed by the system controller 12.

If the pump controller application 120 response indicates that the pump14 a-14 c is ready to dispense product, the system controllerapplication 66 will determine the amount of product that is to bedispensed, and communicate this to the pump controller application 120.Advantageously, by sending data to the pump 14 a-14 c that allows thepump controller 78 to determine a required run time rather than merely apump OFF/ON command (as is conventional), the system 10 ensures that themotor 80 will not run continuously if the system controller 12 losescommunication with the pump controller 78 after the motor 80 has beenactivated.

In response to receiving the dispense product message from the systemcontroller 12, the pump controller application 120 checks the pumpstatus to verify that the pump 14 a-14 c is ready to dispense product(i.e., there are no active alarms that would preclude dispensingproduct), and activate the motor 80 for an amount of time or number ofrotations calculated to dispense the required amount of product. Thepump controller 78 may accumulate the total motor activation time and/ornumber of rotations (collectively referred to as an activation period)and store this value in memory 116. The accumulated activation periodvalue may be used in estimating remaining squeeze tube service lifeand/or a deterioration in pump flow rate due to wear on the squeeze tube108. The pump controller application 120 may also open the diluent valve48 (when present) for an amount of time sufficient to flush the productinto the washing machine 11, and may monitor the flow sensor 96 toensure that sufficient diluent flow is present. In response to the pumpcontroller application 120 determining that the required amount ofproduct has been delivered to the washing machine 11, the application120 notifies the system controller 12 that the dispensing operation iscomplete. If the pump controller application 120 determines that therequired amount of product was not delivered to the washing machine 11,the application 120 may send an alarm or other error message to thesystem controller 12 so that the system controller 12 can notify thesystem operator.

To increase the reliability of communications over the serial data busnetwork, the system controller 12 may make several attempts to deliverdata packets to the system nodes if no response is received to earliertransmissions. The machine interface and pump serial data bus protocolsmay include both acknowledge (ACK) and negative-acknowledge (NACK)response messages to fully validate system node operation, and may alsoinclude cyclic redundancy checking (CRC) to further ensure datarobustness.

The system controller 12 may periodically interrogate the pumps 14 a-14c to monitor the performance of the motor 80, squeeze tube 108, and anyother system errors or alarms. By way of example, the pump controller 78may track the amount of pump activation time and/or number of rotationsto which the squeeze tube 108 has been subjected and use this data toestimate the remaining service life of the squeeze tube 78. The systemcontroller 12 may obtain operational data from the pump controller 78regarding the estimated remaining squeeze tube service life and displaythis data in a squeeze tube life menu over the user interface 60. Thesystem controller 12 may also include a menu selection that allows thesystem operator to reset the percentage of life remaining statistic foran individual pump 14 a-14 c when that pump's squeeze tube 108 isreplaced. The system controller 12 may also generate system maintenancealerts or alarms based on this squeeze tube percentage of life remainingexceeding a lower threshold (e.g., below 5%), which may be settable bythe system operator. Advantageously, by closely monitoring thepercentage of life remaining, the system controller 12 and/or pumpcontroller 78 may adjust the run time of the motor 80 to compensate forreductions in the volume of product dispensed due to tube wear. Moreadvantageously, by actively monitoring squeeze tube life, thereplacement schedules for squeeze tubes 108 may be extended whilesimultaneously reducing the risk of squeeze tube failure, therebyreducing overall system maintenance costs.

While the present invention has been illustrated by a description of oneor more embodiments thereof and while these embodiments have beendescribed in considerable detail, they are not intended to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. For example, as is understood by a person havingordinary skill in the art, the various functions and methods describedherein may be distributed between the system, pump, and machineinterface controllers in various ways and combinations, so that anycontroller in the system may perform functions currently ascribed toanother controller. The invention in its broader aspects is thereforenot limited to the specific details, representative apparatus andmethod, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thescope of the general inventive concept.

What is claimed is:
 1. A chemical dispensing system for a washingmachine, the system comprising: a machine interface configured to detectone or more trigger signals generated by the washing machine andincluding a first serial data bus interface; a system controllerconfigured to obtain first data indicative of an operational state ofthe washing machine from the machine interface using the first serialdata bus interface.
 2. The system of claim 1 wherein the machineinterface further includes: a processor; and a memory including programcode that, when executed by the processor, causes the machine interfaceto: determine the operational state of the washing machine based on thetrigger signals; and transmit the first data to the system controllerover the first serial data bus interface.
 3. The system of claim 2wherein the machine interface further includes: a trigger signalinterface that couples the processor to the trigger signals and which isconfigured to provide galvanic isolation between the processor and thetrigger signals.
 4. The system of claim 2 wherein the program codefurther causes the machine interface to: store the first data in thememory; and transmit the first data to the system controller in responseto receiving a query from the system controller using the first serialdata bus interface.
 5. The system of claim 1 further comprising: a pumpcontroller in communication with the system controller using a secondserial data bus interface, wherein the system controller is furtherconfigured to: determine an amount of a chemical to be dispensed basedat least in part on the operational state of the washing machine; andtransmit second data indicative of the amount of the chemical to bedispensed to the pump controller via the second serial data businterface.
 6. The system of claim 5 wherein the system controller isconfigured as a master, and the machine interface and the pumpcontroller are each configured as slaves.
 7. The system of claim 5wherein the pump controller is configured to: determine a system status;and in response to receiving a status query from the system controller,transmit third data indicative of the system status to the systemcontroller using the second serial data bus interface.
 8. The system ofclaim 7 wherein the system controller is further configured to transmitthe status query to the pump controller prior to transmitting the seconddata; and only transmit the second data if the system status indicatesan absence of a system alarm.
 9. The system of claim 8 wherein thesystem alarm is an out of product alarm.
 10. The system of claim 1wherein the system controller includes a machine interface power supplyoutput circuit, and the machine interface receives power from themachine interface power supply output circuit through the first serialdata bus interface.
 11. A method of controlling a chemical dispensingsystem, the method comprising: detecting, by a machine interfaceincluding a first serial data bus interface, one or more trigger signalsgenerated by a washing machine; and obtaining, by a system controllerover the first serial data bus interface, first data indicative of anoperational state of the washing machine.
 12. The method of claim 11further comprising: determining, by the machine interface, theoperational state of the washing machine based on the trigger signals;and transmitting, by the machine interface, the first data to the systemcontroller over the first serial data bus interface.
 13. The method ofclaim 12 further comprising: coupling, by a trigger signal interface, aprocessor to the trigger signals; and providing, by the trigger signalinterface, galvanic isolation between the processor and the triggersignals.
 14. The method of claim 12 further comprising: storing, by themachine interface, the first data in a memory; and transmitting, by themachine interface, the first data to the system controller in responseto receiving a query from the system controller.
 15. The method of claim11 further comprising: determining, by the system controller, an amountof a chemical to be dispensed based at least in part on the operationalstate of the washing machine; and transmitting, by the systemcontroller, second data indicative of the amount of the chemical to bedispensed to a pump controller via a second serial data bus interface.16. The method of claim 15 wherein the system controller is configuredas a master, and the machine interface and the pump controller are eachconfigured as slaves.
 17. The method of claim 15 further comprising:determining, by the pump controller, a system status; and in response toreceiving a status query from the system controller, transmitting, bythe pump controller, third data indicative of the system status to thesystem controller using the second serial data bus interface.
 18. Themethod of claim 17 further comprising: prior to transmitting the seconddata, transmitting, by the system controller, the status query to thepump controller; and only transmitting the second data if the systemstatus indicates an absence of a system alarm.
 19. The method of claim11 further comprising: receiving, by the machine interface, powerthrough the first serial data bus interface.
 20. A computer programproduct for controlling a chemical dispensing system, the computerprogram product comprising: a non-transitory computer-readable storagemedium; and program code stored on the non-transitory computer-readablestorage medium that, when executed by one or more processors, causes theone or more processors to: detect, at a machine interface, one or moretrigger signals generated by a washing machine; and transmit, over afirst serial data bus interface, first data indicative of an operationalstate of the washing machine from the machine interface to a systemcontroller.